Transport Layer :

This layer is charged to establish connections, to maintain the quality of connection and to stop the latter in an ordered way once the finished conversation. If it is allowed that the network layer is responsible for the communication of processor has processor, the transport layer ensures the communication of process has process, according to the protocol, it can provide mechanisms of safety and guarantee the integrity of the DATA FROM beginning to end. Here some examples of the tasks which this layer can carry out:

• To identify the individual process in the system.
• To make sure that information arrives in the correct order.
• To detect any possible corruption in the individual packages.
• To acknowledge receipt of each packages.
• To implement the mechanisms of recovery of the data.

The protocols according to are currently used by this layer:

• TCP (Transmission Control Protocol), a component of continuation TCP/IP.
• SPX (Sequenced Packet eXchange), a component of the continuation Novell.

To privilege speed, certain implementation give up the use of acknowledgement of delivery and allocate the responsibility for the correction of errors to the protocols of roadbase. The following protocols are used in this case:

• UDP (User Datagram Protocol), a component of continuation TCP/IP.
• IPX (Internetwork Packet eXchange), a component of the continuation Novell.

Easy : This layer of OSI model guarantees that the receiver receives the DATA such as they were sent. With TCP/IP this function is fulfilled with TCP However, TCP/IP offers a second service of transport, UDP (User Datagram Protocol) which does not carry out the checks finale of good communication.